Fine particle iron oxide prepared by aerosol pyrolysis of the iron storage protein ferritin

Abstract

Ferritin is a naturally occurring iron storage protein comprising spherical 6 mn diameter cores of hydrated iron oxyhydroxide surrounded by an organic shell. We present here early results on the aerosol pyrolysis of dilute dispersions of ferritin in water, a project undertaken with a view towards preparing monodisperse magnetic nanoparticles as model systems for studies of fine particle magnetism. Ferritin solution was prepared by rehydrating 4.2 mg of freeze dried native horse spleen ferritin in 50 ml of distilled, deionised and millipore filtered water. This solution was passed through a Bernoulli effect nebuliser and the resultant aerosol was carried through a pair of tube furnaces by compressed nitrogen gas, at a rate of approximately 3 1 s-l. The first oven temperature was held at 600 “C while the second oven temperature was held at 500, 600 and 700 “C in three separate runs. Particulate deposits were captured on nuclepore filters over 40 to 60 minute periods.